Sotalol is a new beta-adrenoceptor blocking drug without membrane stabilizing activity, without intrinsic sympathomimetic activity and with a low cardio-depressive effect. This beta-blocking agent has an half-life much longer than the other beta-blockers (T 1/2 from 10 to 13 hours). The antihypertensive effect and tolerance of 160 mg tablets of sotalol were studied in 35 hypertensive patients aged 18 to 60 years. The drug was administred once daily in the morning. Sotalol prescribed as the only antihypertensive drug lowered the blood pressure to normal values in 21 cases with a single daily of 1 to 3 tablets. In 8 patients a partial response was obtained (25 % reduction of the initial systolic and diatolic pressure). Six patients did not respond. The clinical and biological tolerances were good; Sotalol was only discontinued in three cases. Sotalol appears to be an effective and well tolerated antihypertensive agent, specially for the treatment of moderate and recent essential hypertension in young patients.